DTC P0703 Or P1703: Brake Switch Malfunction: Condition

DTCs indicate that when brake pedal was applied during KOER on-demand self-test, BPP signal did not cycle high and low. Possible causes for this fault are:

Brake pedal not applied during self-test.
Brake pedal applied during entire self-test.
Open or short brakelight circuit.
Open or short BPP circuit.
Faulty BPP switch.
Faulty Powertrain Control Module (PCM).

Verify Brake Pedal Was Depressed

If brake was not applied and released during KOER on-demand self-test, repeat test. Depress and release brake pedal only once during test. If pedal was applied and released, go to step 3).

KOEO DTC P0703 Or P1703

These DTCs indicate that BPP signal voltage was high during KOEO on-demand self-test. Possible causes for these faults are:
- Brake pedal applied during self-test.
- Open or short BPP circuit.
- All brakelights open.
- Faulty brakelight ground.
- Faulty BPP switch.
If brake was applied during KOEO on-demand self-test, repeat test. DO NOT apply brake during self-test. If pedal was not applied, go to next step.

Check Operation Of Brakelights

Check operation of brakelights. If brakelights operate normally, go to next step. If brakelights do not operate properly, go to step 5) (brakelights never on) or step 7) (brakelights always on).

Check For BPP PID Cycling

Turn ignition on. Using scan tool, select BPP PID from PID/DATA monitor menu. While observing PID, apply and release brake several times.

NOTE: If BPP PID is not available, go to step 10). If PID does not cycle ON and OFF, go to step 10). If PID cycles ON and OFF, go to DIAGNOSTIC TEST Z (INTERMITTENT) , step 10).

Check For Power To BBP Switch
Ensure related fuses and brakelight bulbs are good. Disconnect BPP switch (located on brake pedal). Measure B+ input voltage between BPP switch wiring harness connector and chassis ground. If voltage is greater than 10 volts, go to next step. If voltage is 10 volts or less, repair open in B+ circuit to BPP switch.

Check BPP Switch

Depress brake pedal. Measure resistance between BPP switch terminals. If resistance is 5 ohms or more, replace BPP switch. If resistance is less than 5 ohms, repair open circuit between BPP switch and brakelight ground.

Verify BPP Switch Is Not Always Closed

Ensure ignition is off. Disconnect BPP switch (located on brake pedal). Turn ignition on. If brakelights are still on, go to next step. If brakelights are off, verify correct installation of BPP switch. If installation is okay, replace BPP switch.

Check For Short To Power In PCM

Turn ignition off. Disconnect PCM 104-pin connector. Turn ignition on. Check brakelights. If brakelights are still on, go to next step. If brakelights are off, replace PCM.

Check For Short To Power

Turn ignition off. Ensure PCM and BPP switch are disconnected. One at a time, disconnect all modules associated with brakelight circuit. After disconnecting each module, turn ignition on and check brakelights. Turn ignition off. Repeat until each associated module has been disconnected or brakelights turn off. If brakelights are still on after disconnecting all associated modules, repair short to power in BPP circuit. If brakelights are off with associated module(s) disconnected, diagnose appropriate module and/or related system. See DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS in MODULE COMMUNICATIONS NETWORK article in the ACCESSORIES/SAFETY EQUIP section to determine articles that are associated with module that was disconnected to eliminate short to power. Repair system or replace module as necessary.

Check For BPP Circuit Cycling

Turn ignition off. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure voltage between test pin No. 92 and chassis ground while applying and releasing brake. If voltage cycles on and off, replace PCM. If voltage does not cycle, repair open in BPP circuit between PCM and BPP circuit connection to brakelight B+ circuit.